Cellulosic textile finishing process and product



United States Patent 10, 15 Claims. (Cl. 8116.3)

This application is a continuation-in-part of the Fritz Munzel U.S.application Serial No. 111,900, filed May 23, 1961.

This invention relates to an improved finished cellulosic textileproduct and to a process for very substantially enhancing certain of thephysical or mechanical properties of a conventional crease-resistantfinished cellulosic textile material. More particularly, it relates toan aldehydeor resin-finished cellulosic textile material exhibiting verysubstantially improved crease resistance, tensile or tearing strengthand abrasive strength, and to a method whereby the properties ofconventional aldehydeor resin-finished cellulosic textiles can be soimproved.

The term cellulosic textile material as employed herein is intended toinclude films, yarns, fibers, filaments or threads as such or in theform of cast sheets or woven, knit, felted or non-woven fabrics,consisting of natural or regenerated cellulose or a mixture of naturaland regenerated cellulose. The term is also intended to include suchfabrics, films, yarns, sheets, etc., which are made up .of a majorportion of cellulose or regenerated cellulose and a minor portion ofnon-cellulosic material.

.The invention is particularly directed to a method for improvingcertain of the physical or mechanical properties of an already finishedcellulosic textile, as measured by the dry crease angle, tensile ortearing strength and abrasive strength of the article. By an alreadyfinished cellulosic textile we mean one which has been finished bytreatment with a cross-linking chemical, such as one of the aldehydes,or witha resin-forming substance, for example a resin precondensate withthe use of catalysts and in most instances with the application ofelevated temperatures above about 100 C. to effect cross-linking throughthe aldehyde or to cure the resin-forming substance or precondensate inan on the textile.

The aforementioned finishing techniques are well-known in the art andare referred to herein as conventional. These finishes are applied to acellulosic textile fabric, for example, to impart crease resistance and/or dimensional stability to the goods. It is well-known to treatcellulosic textiles in swollen condition with an aldehyde in an aqueoussolution containing an appreciable quantity of sulfuric acid. .Thistreatment imparts a good wet crease resistance. That is to say, creasesformed during laundering disappear during drying. However, the drycrease resistance, that is the capability of the fabric to recover in ashort time after creasing in the dry state is not appreciably improvedby such aldehyde treatment. The application of a resin-formingsubstance, i.e., a resin precondensate, on the other hand, tends toenhance the dry crease resistance of the goods. However, both treatmentshave a salient disadvantage in that they very appreciably reduce thestrength of the cellulosic fibers of the fabric, for example.

While the exact mechanism whereby crease resistance is improved by theaforementioned conventional finishing techniques is not completelyunderstood, it is believed that the aldehyde treatment produces achemical cross-linking between molecules of the cellulose or regeneratedcellulose through an aldehyde bridge. In the case of resin-formingsubstances or resin precondensates, e.g. melamine-form-' aldehyde, it isbelieved that the essential reaction during condensation and curing isone of resin formation as distinguished from grafting or cross-linkingwith the cellulosic molecule, although of course some cross-linking andgrafting may occur. It is believed that the condensed, cured resin isfor the most part simply adhered to the cellulosic molecule rather thanregularly and repeatedly linked chemically therewith.

In accordance with the present invention We have found that the drycrease resistance, tearing strength and abrasive strength of the textilecan be very substantially improved, and in fact a highly acceptablecellulosic textile bearing the aldehyde or resin finish can be producedif the thus finished material is subjected to a critical total dose ofionizing radiation between about 10 and 5x 10 rad. While theconventional finish alone increases the crease resistance of the textileso treated, this increase is at the expense of very substantiallyreduced tensile or tearing and abrasive strengths of the goods. Themethod of the present invention not only still further increases the drycrease resistance of the textile, but very greatly enhances, for exampleas much as two to four times, the tearing strength and abrasion strengthof the goods.

While this application is directed primarily to the improvement andrejuvenation of the aforementioned physical or mechanical properties ofan already conventionally finished cellulosic textile, it is also withinthe scope of the present invention to carry out an aldehyde or aresinforming operation on an unfinished cellulosic textile, and thenfollow this finishing treatment with the application of theaforementioned dose of ionizing radiation.

The ionizing-radiation employed in the present process may be of theelectromagnetic type, for example gamma or X-rays. Suitable sources ofgamma include C0 fission products of U and separated isotopes such as Csetc. Alternatively, the ionizing radiation may consist of acceleratedelectrons, i.e. beta particles, but of a relatively low particle energy,namely between about 0.05 and l mev., preferably between about 0.05 and0.6 mev., which may be produced With the aid of the usual electronacceleraters, such as the cascade, Van de Graaf or linear types, or fromradioactive substances such as Sr An important aspect of the presentinvention is the use of accelerated electrons of the aforementioned lowenergy values. It has been found that these low energy beta particles,that is, not above 1 mev., enable achievement of the improvementspossible by the present method without any significant degradation ofthe cellulose or regenerated cellulose molecule. At energy levels aboveabout 1 mev. and equivalent total dose very significant deterioration ofthe cellulose occurs. The importance of the use of low energy betaparticles is set forth in the related application of Fritz Munzel,Serial No. 125,089, filed on even date herewith, and the informationtherein with respect to the importance of the use of low energyparticles I ing application contain molecular groups capable ofabsorbing ionizing radiation energy and resonating or transe ferringexcitation energy to the cellulosic molecule. The action of thesensitizers is to ultimately very greatly enhanCe the effect of ionizingradiation upon the finished textile, while also by reason of theirabsorptive and resonating efiiciency they serve to reduce the total dosewhich must be imparted to the textile to achieve the outstandingimprovements attending the present process. A variety of materialssuitable as sensitizers is set forth in the aforementioned copendingapplication, and a particularly preferred material is1,4-diphenylbenzene. The sensitizers are preferably applied to thecellulosic textile by application from aqueous media followed bysqueezing off and 1 drying with the sensitized, conventionally finishedtextile then being ready for irradiation.

As cross-linking chemicals which may be employed in the conventionalfinishing above referred to, or which may be employed in the presentprocess as a preliminary step to irradiation we intend the aldehydes,such as formaldehyde, adipic aldehyde, glyoxal, etc. The textile istreated in the swollen state in an acid medium with the aldehyde, washedout and subsequently subjected to irradiation in wet or dry condition.It is also possible to impregnate the textile with an aqueous solutionof the aldehyde and an acid catalyst, subsequently heat the'impregnatedtextile for a short time above 100 C., wash, and then irradiate in wetor dry condition.

Where finishing is with resin-forming substances, the textile isimpregnated therewith as from a dispersion or solution of theresin-forming substance which generally also contains a condensationcatalyst. Following impregnation, the excess resin-forming substance issqueezed out and the impregnated fabric is then subjected totemperatures above about 100 C. for a period of time sufficient toeffect curing. Typical resin-forming substances are those customarilyemployed in the crease-proof finishing of cellulosic textiles byconventional methods which do not employ irradiation. They are compoundswhich contain oxygen in the molecule or which contain sulphur in placeof oxygen, as in urea and thiourea. Typical condensable or resin-formingsubstances include precondensates of formaldehyde with urea, thiourea,ethyleneurea and its homologues, uron, acetylene-diurene and itsderivatives, dicyandiamide, melamine, phenol and its derivatives,methylolurea, methylolamines. Also suitable are ketone-aldehydeprecondensates, aziridinyl compounds, triazone derivatives and diglycideethers. Particularly useful resin-forming substances includetetrahydro-1,3-bis (methoxymethyl) -5-methyl-2( 1 -s-triazone, asdescribed in US. Patent No. 2,373,135 or 1-carbony1-2,5-dimethoxy-4-ethyl-triazone-2,4,6, and othersimilar triazone derivatives, as wellas glycol polyacetals, for example as described in US. Patent No.2,786,081, among other wellknown cellulosic textile finishing materials.Mixtures of two or more of these resin-forming substances can of coursebe employed.

The method of the present invention is applicable to textiles of allkinds, as noted above, particularly to fabrics or sheet material. Themethod is suited primarily for crease-proofing and imparting dimensionalstability. However, it is also possible by this method to producepermanent embossing effects such as gotfering, ribbing, schreinering andmoire effects as well as calendaring effects with or without friction.The method can of course be applied to textile yarns, filaments orthreads. Moreover, very good crease resistance and dimensional stabilitycan be achieved in fabrics containing relatively highly twisted yarns,such as are employed in the pro duction of voiles and marquisettes,which materials show a strong tendency to shrink. The textile materialstreated in accordance with the present invention also retain a pleasantsoft hand.

The instant method will be further apparent from the following typicalexamples which illustrate practical applications thereof and illustratecertain characteristics of the novel finished textile products.

4 Example I A cotton imitation poplin fabric was treated with thefollowing formaldehyde solution at 34 C. for seconds:

Formaldehyde (37 percent by volume) 250 Sulfuric acid 66 B 350 Water 400Crease Angle Tearing Abrasive in degrees Strength in g. Strength innumber of revolutions Warp Fill Warp Fill Starting Material 40 45 605595 14, 390 Section A 79 81 420 480 10, 850 Section B- 920 1, 010 38,000

The tearing strength was determined with an Elmendorf Tearing Tester onstrips 2.5 cm. wide and 16.5 cm. long. Abrasive strength was measuredwith an apparatus having a disc covered with a standardized wood clothwhich was rotated on the surface of the fabric, and the number ofrevolutions noted at the time of fabric failure. Crease angles weredetermined as follows: 3 x 5 cm. strips of the starting and treatedfabrics were folded in the warp or fill direction, respectively, andplaced under a weight of 1 kg. for one hour. After removal of the weightthe materials were left unweighted for 15 minutes and the crease anglesthereupon measured.

Example 11 v A cotton imitation poplin fabric was treated with theformaldehyde solution of Example I at 30 C. for a period of 15 seconds,and thereupon rinsed with water in accordance with Example I, treatedwith ammonia, rinsed again and dried. The thus treated fabric contained0.18% by weight formaldehyde bound to the cellulose. Two sections, A andB, were detached and Section B was treated at 20 C., in a water bathcontaining about 1% of 1,4-diphenylbenzene, and subsequently dried at60-70 C. Thereupon Section B was irradiated as described in Example I.Mechanical properties of the starting fabric, finished Section A andfinished-irradiation Section B were as follows:

aqueous solution of dimethylolethyleneurea containing 15 g./l. of zincnitrate catalyst, squeezed out and predried at 60-70" C. The fabric wasthen heated to C. for four minutes, washed out and dried. Two sections,A and B, were detached from the thus treated fabric,

and Section B was subjected to gamma radiation from a C source to .atotal dose of 7.2 10 rad. Changes in the mechanical properties of thestarting fabric, finished Section A and finished-irradiated Section Bwere as follows:

solution containing 2 g. of a sulphonated fatty alcohol and 0.5 g. ofsoda in a liter of water, then rinsed with water and dried at 60 C. Twosections, A and B, were detached from the thus treated fabric andsubjected to the action of accelerated electrons of a particle energy of0.1 mev. to total doses of 10 and 2X10 rad, respectively. The propertiesof the unfinished starting ma- Crease An le Tearin Abrasive in degree%Strength 51g. Strengthin terial, Sect1on A and Sect1on B were asfollows:

number of revolutions Warp 11111 Warp Fill 10 Crease Angle TearingAbrasive Starting Material n 45 50 570 620 10, 380 degrees strength sectonA 117 125 310 285 11,120 revolutions Section B, Irradiated" 115 120720 780 14, 860 Warp m Warp Fm v 15 St t v1 te 1 1 47 59 880 880 15 400at ing 1 a t a Example 1V Section 110 10s 1, 030 1,030 20,810 SectwnB105 100 1,110 1,110 19, 580 A cotton imitation poplin fabnc wasimpregnated with a 15% aqueous solution of 1-carbonyl-2,6-dimethoxy-4-ethyl-triazone-2,4,6. The solution contained no catalyst. Example VIIThe fabric was subsequently squeezed out, predried at 6070 C. and thenheated to 140 C. for four minutes, washed out and dried. Two sections, Aand B, were detached from the thus treated fabric and Section B wassubjected to gamma radiation from a C0 source to a total dose of 10 rad.The mechanical properties of the starting material, finished Section Aand finishedirradiated Section B were as follows:

A bleached spun rayon calico was impregnated with an aqueous solutioncontaining per liter 100 cc. of formaldehyde (technical grade, 40%) 20g. of zinc chloride and 20 g. of alum, squeezed out, stretched slightlyover its desired finished proportions and predried at 60 C. The fabricwas subsequently heated to about 130 C. for one minute, acidulated with5 g. of 80% acetic acid and a liter of water, rinsed with coldwater,squeezed out, stretched to the desired finished proportions and dried.The thus treated fabric was exposed to a stream of accelerated electronsof a particle energy of 0.12 mev. to a total dose of 10 rad. As comparedwith the starting material, the formaldehyde treated-irradiated bleachedspun rayon calico exhibited a substantially increased crease angle asWell as increased abrasive and tearing strengths.

It will be apparent from the foregoing examples that treatment withionizing radiation in accordance with the present inventionsubstantially increases the crease angle of an already conventionallyfinished cellulosic textile. Significant improvement will also be notedin the tearing and abrasive strengths of finished-irradiated Section Bas compared with the starting or unfinished fabric.

The following Examples VI-IX further illustrate the present methodemploying different finishing materials and different total doses ofionizing radiation on the same fabric.

Example VI A cotton imitation poplinfabric was impregnated with anaqueous solution containing per liter of water 110 g. of amelamine-formaldehyde precondensate and 10 g. of magnesium chloridecatalyst, squeezed out and dried at about 60 C. The fabric was thereuponheated to 150 C. for five minutes, washed for five minutes in a Thestarting fabric of Example VI was impregnated with a solution containing300 g. of a urea-formaldehyde precondensate and 24 g. of magnesiumchloride catalyst in one liter of Water, squeezed out and dried at C.Further treatment and irradiation were then carried out as described inExample V1 with the following results:

The starting fabric of Example VI was impregnated with a solutioncontaining 120 g. of an epoxy resin based on a glycidyl ether and 6 g.of zinc fluoborate (40%) catalyst, in a liter of water, squeezed out anddried at 60 C. Further treatment and irradiation were then carried outas described in Example V1, with the following results:

Crease Angle Tearing Abrasive in degrees Strength in g. Strength innumber of revolutions Warp Fill Warp Fill Starting Material 47 59 880880 15, 400 1 Section A. 110 115 1, 230 1,100 23, 760 Section B. 110 1201,050 1, 050 25, 880

Example IX The starting fabric of Example VI was impregnated with asolution containing g. of a glycol polyacetal of the following formula:

- 7' source to total doses of 2.5 10 7.5 and 125x10 respectively. Theresults were as follows:

1. A process which comprises subjecting a conventional creaseresistant-finished cellulosic textile material to high energy ionizingradiation to a total dose between about 10 and 5 10 rad. to improve thecrease resistance, tearing strength and abrasive strength of the creaseresistance-finished textile.

2. A method as set forth in claim 1 wherein the creaseresistant finishedtextile is irradiated in the presence of 1,4-diphenylbenzene in contactwith said textile.

3. A process as set forth in claim 1 wherein the finished textile issubjected to accelerated electron radiation of a particle energy betweenabout 0.05 and 1 mev.

4. A process as set forth in claim 3 wherein the accelerated electronparticle energy is betweenabout 0.05 and 0.6 mev.

5. A process which comprises subjecting .a conventional chemicallycross-linked finished cellulosic textile material to high energyionizing radiation to a total dose between about 10 and 5 10 rad. toimprove the dry crease resistance, tearing strengthand abrasive strengthof the chemically cross-linked finished textile.

6. A process as set forth in claim 5 wherein the crosslinking chemicalis an aldehyde capable of cross-linking with the cellulose of thetextile.

7. A process as set forth in claim 5 wherein the cross-linking chemicalis a resin preoondensate.

8. A process which comprises subjecting a cellulosic textile materialwhich has been conventionally finished with a resin-forming substance tohigh energy ionizing radiation to a total dose between about 10 and 5X10rad. to improve the crease resistance, tearing strength and abrasivestrength of the conventional resin-finished textile.

9. In a method of finishing a cellulosic textile material includingtreating the cellulosic textile in a swollen condition with an aldehydecapable of cross-linking with the cellulosic textile material in thepresence of an acid re- E5 acting material, Washing and drying thealdehyde-treated textile, the improvement comprising subjecting the sotreated textile to high energy ionizing radiation to a total dosebetween about 10 and 5 l0 rad., to improve the dry crease resistance,tearing strength and abrasive strength of the textile.

10. A method as set forth in claim 9 wherein the ionizing radiationcomprises accelerated electrons of a particle energy between about 0.05and 1 mev.

11. In a method of finishing a cellulosic textile material to improvethe crease resistance thereof including treating the textile with aresin-forming substance, condensing and curing the resin, theimprovement comprising subjecting the so treated textile to high energyionizing radiation to a total dose between about 10 and 5X 10 rad. toimprove the crease resistance, tearing strength and abrasion strength ofthe resin finished textile.

12. A method as set forth in claim 11 wherein the ionizing radiationcomprises accelerated electrons of a particle energy between about 0.05and 0.6 mev.

13. A finished cellulosic textile material produced by the process ofclaim 1.

14. A finished cellulosic textile material produced by the process ofclaim 6.

15. A finished cellulosic textile material produced by the process ofclaim 8.

References (Zited by the Examiner Pan, Textile Research Journal, vol.29, 415-421 (1959). Porter, Textile Research Journal, vol. 30, N0. 7,July 1960, pps. 510-520 (pps. 510 and 518 relied-0n).

NORMAN G. TORCI-IIN, Primary Examiner.

, JULIAN S. LEVITT, Examiner.

1. A PROCESS WHICH COMPRISES SUBJECTING A CONVENTIONAL CREASERESISTANT-FINISHED CELLULOSIC TEXTILE MATERIAL TO HIGH ENERGY IONIZINGRADIATION TO A TOTAL DOSE BETWEEN ABOUT 10**5 AND 5 X 10**6 RAD. TOIMPROVE THE CREASE RESISTANCE, TEARING STRENGTH AND ABRASIVE STRENGTH OFTHE CREASE RESISTANCE-FINISHED TEXTILE.